The proposed research centers on the study of activated human growth hormone, compared to clinical grade hGH. Studies of the short term and long term effects in hypopituitarism will be made, initially using metabolic parameters and finally rate of growth itself. In vivo studies comparing these will include glucose and amino acid metabolism in adipose tissue and in muscle. The mechanisms of cleavage of growth hormone will be studied in the pituitary glands of rodents. For activated human growth hormone radioreceptor and radioimmunoassay methods will be devised. A limited number of short term experiments comparing the two forms of growth hormone with human prolactin will be made. Activated hGH has enhanced prolactin activity; activated hGH and human prolactin will be studied in receptor and radioimmunoassays for competitive binding properties to prepare for surveying plasma of breast cancer patients.